In the past, in a semiconductor-manufacturing apparatus used in an etching process in which a plasma process forms the mainstream, a CVD film-forming process, and an ashing process which removes a resist among semiconductor-manufacturing processes, members were exposed to halogen-based corrosive gas, such as highly reactive fluorine or chlorine. Therefore, as a material of the members, ceramic materials which are materials having excellent corrosion resistance with respect to plasma or corrosive halogen gas are used.
In addition, the members are members which need to be conductive like a plasma focus ring having a function of focusing plasma on a wafer surface, a showerhead electrode having a role of an electrode, and the like, and are also members which need to be insulating like a chamber wall which allows high frequency penetration, a pedestal which holds wafers, a clamp ring which holds focus rings and wafers, a jig which fixes electrode, and the like. Therefore, depending on use, both insulating ceramics and conductive ceramics are used.
As the insulating ceramics, oxide ceramics, such as aluminum oxide (Al2O3) and yttrium oxide (Y2O3), are used. In addition, as the conductive ceramics, ceramics which are a single body and develop conductivity, such as silicon carbide (SiC), and combined ceramics that are combined by adding a conductive material, such as silicon carbide (SiC), carbon (C) or metal, to an insulating ceramic are used.
As the combined ceramics, for example, conductive ceramics obtained by adding a conductive material, such as metal yttrium, carbon, yttrium nitride or yttrium carbide, to yttrium oxide (Y2O3), which is an insulating ceramic, are proposed (Patent Document 1).
In addition, among semiconductor-manufacturing apparatuses, in an etching apparatus using plasma, a CVD apparatus, an ashing apparatus, and the like, ceramic members obtained by combining and integrating an insulating ceramic and a conductive ceramic are used.
These ceramic members are obtained by working an insulating ceramic and a conductive ceramic into predetermined shapes respectively, and adhering both ceramics using an adhesive or mechanically joining both ceramics using clamps, screws, bolts, or the like. In a case in which an adhesive is used, an organic-based adhesive, such as epoxy, cannot be used due to its corrosion resistance and heat resistance, and therefore an inorganic-based adhesive is used. In this case, the thermal expansion coefficient of the adhesive is matched to any of the insulating ceramic and the conductive ceramic.